Sure there are reasons and good ones too.
If you were in charges of the budget how do you justify the expense and time spent on developing handgun load data for a shotgun powder when your company has plenty of data for the handgun powders they sell? It is very expensive to develops the data and takes away access to the equipment when it's needed to test and develop new powders.
Like I already said, when powders were few we used what we had and crossed over a lot. It's no longer necessary and we are lucky to have so many good choices available to us today. I no longer use Red Dot or Green Dot in handgun loading and never did use Blue Dot and rarely used Herco. Nothing wrong with any of them but now days there are better choices available which are more accurate and cleaner. (although I wouldn't hesitant to go back to Red Dot/Promo if need be)
Blue Dot is one of the best powders for 10mm full power loads.